The objective of the study is to evaluate the safety and efficacy of 1.1, 0.5, 1, 2, and 5 mg. t.i.d. of Voglibose when administered orally, to 666 NIDDM patients for 26 weeks as compared to a matching placebo, following a placebo-controlled eight week lead-in period. The primary efficacy parameter will be the change in HbA1c from baseline to endpoint. Secondary efficacy parameters will be fasting blood glucose, postprandial blood glucose, self-monitored blood glucose (SMBG), fsting insulin and C- peptide, glucose tolerance test, triglycerides, cholesterol (total, HDL and LDL) & HbA1c responder rate.